It isn’t just stomach acid which breaks down food in your gut. You also have armies of bacteria in your gut which feed off of undigested carbohydrates (like sugars and fiber). When the bacteria eat the carbs, they produce gases as a byproduct. Before you get scared about the idea of bacteria in your gut, you need to know that it is normal and even healthy to have certain amounts of some types of bacteria in your body. The problem occurs when you have too much or the wrong type of bacteria in your gut — such as is the gas with SIBO (Small Intestinal Bacterial Overgrowth syndrome).

There are many ways to diagnose SIBO (which we talked about in the last part of this series). However, there are a lot of limitations with many of these diagnosis methods. The best way to diagnose SIBO is with breath tests. These tests measure the amounts of certain gases in your gut. If the levels are high, then it indicates that bacteria levels are too high.

What Are Breath Tests Used For?

The bacteria in our guts feed off of carbohydrates. They produce gases as a byproduct. Some of the gases are then absorbed through the lining of the colon and get into our blood. From there, the gases make it to our lungs and are exhaled in our breath.

Breath tests aren’t just used to diagnose SIBO. They can also be used to diagnose H. pylori, lactose intolerance, and fructose intolerance. However, it is important to note that the breath tests are slightly different for each of these conditions. For example, the bacteria H. pylori produces carbon dioxide, so this is the gas that labs will be looking for in the breath test samples.1 (Read about how to treat H. pylori naturally here)

To diagnose SIBO with breath tests, labs need to look for elevated levels of hydrogen and/or methane. Note that there is a difference between Hydrogen SIBO and Methane SIBO, which we will address later in the series.

How SIBO Breath Tests Are Performed

You can order SIBO breath tests to take at home, or you can perform them at the lab. You will be required to fast for at least 12 hours before the test is taken. That means no food, but prescription meds and water are okay. You will also have to follow a special diet for 1-2 days before the test. The diet basically removes any fermentable foods so you don’t have gas in your GI tract prior to the test and get a false positive.

To take the test, you first breath into a little tube (pictured below) to measure your base hydrogen and methane levels. Then you drink a special solution of lactulose or glucose. You breathe into the tubes again every 20 minutes. To do it, you just breathe into them through a cocktail straw for a few seconds. You will see the condensation form. Then put the lid on and restart your timer. The test measures how the levels of hydrogen and methane change. A positive SIBO breath test is defined as one where there are peaks of hydrogen and/or methane after taking the sugar solution.2

These are the suckers I had to breath in every 20 minutes for the SIBO breath test

You Must Test for Both Hydrogen and Methane

If your doctor tells you to get a test for just hydrogen, you should insist on testing for methane (and also consider switching specialists!). The bacteria in your gut feed off of carbohydrates and produce hydrogen as a byproduct. However, 8-27% of people do not have detectable levels of hydrogen production in their guts from bacteria. Instead, they produce methane. This is because our guts also contain archaea, which are similar to bacteria but in a different kingdom of organisms. Archaea feed off of hydrogen and produce methane gas as a byproduct. So, a bacterial overgrowth could cause increases in hydrogen, methane, or both. We will get into this more in the next section of the series about the difference between Hydrogen and Methane SIBO.

Further, certain types of bacteria in the gut produce methane instead of hydrogen. Some of these include: Staphylococcus aureus,Streptococcus viridans, Enterococci, Serratia and Pseudomonas species. If you were to test just for hydrogen, you could miss overgrowths of these bacteria and get a false negative.3

Here is what my breath test looked like. You can see that methane levels are elevated – which is why it is so important to test for both hydrogen and methane:

Here is what my breath test looked like. You can see that methane levels are elevated – which is why it is so important to test for both hydrogen and methane

Lactulose vs. Glucose SIBO Breath Tests

Both lactulose and glucose are types of sugars. Not sugar as in the white stuff you buy in supermarkets, but sugar as in the substance that our bodies break carbohydrates down into. Bacteria digest the sugars and produce gas as a byproduct, which can be measured in a breath test.

There are also other breath tests available, such as one using the sugar xylose, but these aren’t as reliable and may give a false negative.

Glucose Tests: Both humans and bacteria absorb glucose. We humans absorb it in the first three feet of the small intestine. If the glucose breath test shows that gas levels rise, it means that SIBO is present in the first part of the small intestine. It doesn’t tell us anything about whether SIBO is present in the end of the small intestine.

Are considered more accurate

But won’t diagnose SIBO in the end of the small intestine (which is where it is more common).

Lactulose Tests: Humans don’t absorb or digest lactulose — only bacteria in our bodies will do that and will produce gas as a result. The test isn’t as accurate as glucose tests, but they can detect SIBO in the end of the small intestine, which is where it is considered more common.

Not as accurate as glucose tests

But will diagnose SIBO in the end of the small intestine.

3-Hour Lactulose Test is the Gold Standard

The 3-Hour Lactulose breath test is considered the Gold Standard for diagnosing SIBO. Unfortunately, most laboratories only offer shorter tests. These shorter tests aren’t as reliable because it takes time for hydrogen and methane to travel through the gastrointestinal tract, into the blood, and out the lungs into our breath.4

The bottom line? Choose a lab test with a longer time.

UPDATE:

Good news! There are now SIBO breath tests that you can order directly without a doctor’s order! While I’m a HUGE fan of having a doctor’s guidance, I understand the need to know whether you have SIBO or not before you invest in a practitioner.

You can order the test and it will be sent to your home (note that some states still don’t allow you to order tests; sorry).

***Use the coupon code HOLLYWOOD to get an additional $5 off. The coupon applies to all lab tests that you order!

Ready to eliminate SIBO once and for all? Get your copy of The SIBO Solution: Your Comprehensive Guide to Eliminating Small Intestinal Bacterial Overgrowth by clicking HERE. You’ll also receive a BONUS SIBO Detox Support Guide mini ebook with your purchase.

Sylvie McCracken is a former celebrity assistant in Hollywood turned full time entrepreneur currently living in Ashland, Oregon with her husband and 3 kids. She writes about treating and preventing health conditions with real food and natural remedies, as well as anything else she feels like writing about because she's a rebel like that. 😉 She also mentors entrepreneurs on her other site, SylvieMcCracken.com

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20 Comments

DarekMay 16, 2017 @ 07:13:26

Hi Sylvie,
Wonderful blog and amazing work( btw. but I need improve my english to understand more ;P)
I did lactulose hydrogen breath test and before I visit my doctor I just wanna know what it can mean, because I read somewhere that breath test can show lazy bowel syndrome. I’m affraid of antibiotics a little because in microflora test came out dysbiosis. I will be grateful for having a look on my test .
15g of lactulose:
1. 1 ppm 9.20
2. 2 ppm 9.40
3. 2 ppm 10.00
4. 4 ppm 10.20
5. 6 ppm 10.40
6. 36 ppm 11.00
7. 48 ppm 11.20
8. 44 ppm 11.40
9. 55 ppm 12.00
10. 60 ppm 12.20
If that means SIBO or someting else. What should I think about it. Thank you in advance.
Greetings from Poland.

Sylvie, The test you now reference in the update is in fact a lactulose test (albeit 2hrs). I’m letting you know because you reference this test on your sibo solution resources page and state this: “The bad news is it’s only a 2 hour test, not a 3 hour test and that it’s a glucose test not a lactulose test.” I have ordered this test and can confirm that the substrate is lactulose. Which begs the question why should we need a prescription for a 3hr lactulose test but not a 2hr lactulose test? I think for my next followup I’ll order this 2hr lactulose test but shift the sampling out to cover 3hrs. As an aside, this company has not been very responsive to questions via their support email.

I did the Genova lactulose test a while back and it was negative and I was shocked, because I was sure I had it. My symptoms were textbook. I have fermentable farts (I’ll fart and then like clockwork will again in a couple minutes over and over in this consistent pattern) and I often burp and have indigestion. This is all regardless of diet. I have been sick for awhile (chronic insomnia) and now have a breast cancer diagnosis. No parasites, no h.ylori. I’ve had all the tests and despite losing 35 pounds, I still have these symptoms. Despite multiple cleanses. Whether I’m on the SCD diet or on a plant based whole food diet. I have chosen to cure my own cancer as I believe I can and have already seen progress but the gas, bloating and indigestion/burping continues. So, Is the Genova test reliable? Also, I don’t want to take another test as sugar is no good for cancer. Can I treat SIBO without getting the test? I do coffee enemas every day which will relieve some of the gas and bloating but it always returns!

Sorry to hear that Anita. I don’t have personal experience with the Genova test. (I wrote more about breath tests here: http://www.hollywoodhomestead.com/breath-tests/). Has your doc not suggested testing for other GI issues? The thing is if you don’t have SIBO and you treat for SIBO, depending on what you use for that, you could exacerbate whatever else you have…

Did SIBO make you have bad breath? Especially if tested positive on methane.. Or did H Pylori make you have bad breath? Curious because I have symptoms of both, and bad breath. I wonder if its linked. My oral Hygeine is perfect! Dentist uses my teeth as an example to others.

I did a lactulose test through Genova Labs recently, which took about 3 hours to do, is this a recommended test? I am still waiting for the results. I recently did a hydrogen test that took two hours, and it was negative.

Hollywood Homestead Thank You 🙂 I was going to send the glucose one back until I heard Mark Pimental saying that fpr constipation, methane dominant, it doesnt matter, as the methane will likely be there from baseline anyway. THANKs so much for your site and sharing. Im going to make my own site about ibs/sibo and will link to you as a resource. Thanks again. Bhavani.

Hollywood Homestead Thank You 🙂 I was going to send the glucose one back until I heard Mark Pimental saying that fpr constipation, methane dominant, it doesnt matter, as the methane will likely be there from baseline anyway. THANKs so much for your site and sharing. Im going to make my own site about ibs/sibo and will link to you as a resource. Thanks again. Bhavani.

Welcome to Hollywood Homestead. I’m Sylvie, a former celebrity assistant in Hollywood turned full time entrepreneur currently living in Southern Oregon with my husband and 3 kids. I write about treating and preventing health conditions with real food and natural remedies. See you in the comments!

Statements on this site have not been evaluated by the FDA. Neither our products nor our literature are intended to diagnose, treat, cure or prevent any disease. Please consult your doctor before beginning any natural treatment.

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